It is common practice to mount glass mirrors and the like on a wall using brackets having hooks that engage the edge of the mirror, and various brackets having an adjustable mirror engaging hooks have heretofore been proposed. The adjustable type hooks commonly have a stationary bracket member that is adapted for attachment to a wall as by screws and a movable bracket member that is slidable relative to the stationary bracket member. My prior U.S. Pat. No. 4,238,103 discloses an adjustable mirror mounting bracket in which a spring is arranged to yieldably urge the movable bracket member into a mirror engaging position. While this mirror mounting bracket is well adapted for its intended use, the use of a spring increases the cost of manufacture and assembly. Some other adjustable brackets such as shown in U.S. Pat. No. 2,532,162 are arranged to be manually adjusted and utilize a detent arrangement for holding the movable bracket member in the adjusted position. While this bracket is more economical to fabricate, the corrugations or detents are arranged in a row along the centerline of the stationary bracket and the screw or fastener receiving openings are located at opposite ends of the row of corrugations such that the heads on the mounting screws or fasteners can interfere with or impede adjustment of the movable bracket member in the stationary bracket member. Further, this arrangement requires the stationary bracket to be substantially longer than the adjustment range of the movable bracket member, to provide space for the screw mounting holes at the ends of the row of corrugations.